Numerous information broadcast services, both satellite and terrestrial wired (e.g. cable) and wireless, are available today and future growth in this industry is anticipated. In many cases, these broadcast services offer/require a means for interactive information exchange with the subscriber. Such interaction is typically asymmetric in nature with subscriber stations receiving a much greater amount of information than they transmit. As such, the subscriber station must be equipped with a means of receiving large amounts of information from the broadcast channel and transmitting small amounts of information on the request or backhaul channel (FIG. 1 is a block diagram of the generalized architecture for systems incorporating the invention.) Note also that a means for transparently interconnecting the two independent systems (i.e., the Broadcast Channel and the Backhaul Channel) may be required. This will likely be necessary whether the two systems are owned/operated by a single entity or by different entities.
Currently, the leading ways of providing the backhaul channel is through use of a data modem operating through the public telephone system. In many cases, this approach is convenient and cost effective, requiring a simple wired or cellular connection to the telephone system. Subscribers that desire timely delivery of large amounts of information via satellite may do so from virtually any location in the world so long as a telephone circuit is available for placing requests. However, many applications exist which pass small amounts of request data and would benefit by a wireless solution with greater bandwidth efficiency.
The object of this invention is to provide bandwidth efficient wireless backhaul channel which is a flexible and efficient alternative to the telephone circuit. It is wireless, which precludes physical connection, covers large regions, and can be shared among a subscriber community so as to make better use of bandwidth with the potential for cost benefits for both the user and the broadcast provider. Furthermore, even though the backhaul channel device could be one-way (transmit only) or two-way (transceiver) the backhaul only needs to have a one-way link with the broadcast provider which is more bandwidth efficient for the provider. These features make this solution very attractive for a wide variety of users such as:
Satellite broadcast providers. PA1 Military field personnel. PA1 Emergency response teams. PA1 Travelers (RV's, aircraft) PA1 Boaters. PA1 Automated data collection/reporting sites. PA1 Cable TV subscribers. PA1 The backhaul channel can be independent of the wideband broadcast channel, with any coordination required between the backhaul and broadcast service provider handled in a manner which is transparent, or of little impact, to both. PA1 The subscriber can use this backhaul channel as an alternative to other conventional means; this provides a subscriber with flexibility to circumvent "busy periods" or "service outages" of a given conventional backhaul service provider, and further places the subscriber in the attractive position of selecting the most cost-effective approach. PA1 This approach explicitly exploits the asymmetric nature of information exchange (low rate on backhaul; high rate on broadcast) to: PA1 Control feedback in the form of small data packets may be sent over the broadcast channel to increase capacity on the backhaul channel (e.g., to provide backhaul transmit timing corrections). PA1 Messages, in the form of small data packets, may be sent over the broadcast channel to provide user verification, inform the users of request status, assist in antenna alignment, etc. PA1 The backhaul device can be implemented so that it connects to an existing telco interface connector on the broadcast receiver/modem and responds such that its installation is transparent to the user (or the receiver/modem) and no modification of the existing equipment is required. PA1 Provides connectivity over wide regions, with global connectivity via LEO, GEO, or MEO satellite constellations. PA1 Accommodates system growth. Additional satellite bandwidth may be purchased/leased as the subscriber grows. PA1 Enables flexibility in the overall infrastructure (e.g., gateway locations/design) of the system.
This invention relates to a unique means for providing a backhaul channel. This approach may be used for both satellite and terrestrial broadcast systems as a way of providing a backhaul with the following innovative, advantageous and unique features:
Efficiently use backhaul bandwidth--much more efficient than a telephone channel, which sits idle (but connected) during many broadcast request sessions. PA2 Permit simple, random-access protocols on the backhaul channel. PA2 Allow the use of a very compact, very low-power, device for the backhaul channel--no need for a more complex two-way telephone transceiver; this, for example, frees up the transmit counterpart of the two-way bandwidth of the typical two-way satcom telephone channel for other uses, such as one way paging services.
The remainder of the application addresses the use of satellite communications as the means for implementing the backhaul channel. Note that the use of a wireless terrestrial equivalent for a limited geographic region is also possible.